WO1998010146A1

WO1998010146A1 - Absorption means

Info

Publication number: WO1998010146A1
Application number: PCT/SE1997/001478
Authority: WO
Inventors: Bo SÖDERGREN
Original assignee: Prolup Absorbenter Ab
Priority date: 1996-09-05
Filing date: 1997-09-04
Publication date: 1998-03-12
Also published as: JP2001500203A; EP0925409A1; SE507898C2; PL332721A1; SE9603221L; KR20000068445A; AU4141497A; SE9603221D0; US6326070B1

Abstract

Absorption means of sawdust or fuel pellets that has been freed from its terpene content and thereafter treated with a teflon wax so that the sawdust particles receive a coating of this. The sawdust treated in this way gets the property that it becomes hydrophobic and consequently does not absorb water, at the same time the ability to absorb oil seems to be considerably improved. This absorption means therefore becomes very suitable for the control of oil discharges. Since no water is bound to the sawdust this will also after the absorbing of the oil float on water. In this way the absorption means after fulfilles absorbing is easy to collect.

Description

Absorption means

In order to degrade or collect liquids and contaminations numerous different types of absorption means ar known. Despite this no satisfactory solution exist today for the handling of liquid discharges, as for instance oil discharges. Not only big undesired and unintentional discharges must be minimized but it is also necessary to reduce the damages at smaller discharges since the number of occasions increase steadily. A single workshop that discharge a little oil in the municipal waste net is maybe no great catastrophe, but if several small discharges take place at several locations and repeatedly the pollution load will in the long run become unacceptable. In view of this the invention has as its object to define an absorption means that is practically useful and efficient and a method for the fabrication of this, and a method to use the absoφtion means.

The absoφtion means according to the invention has as its major component saw dust or corresponding that in one way or an other has had the teφene content removed. Dependent of the intended use for the absoφtion means the saw dust has then been treated different. If water or water carried substances are to be absorbed the sawdust is softened. This can be done in different ways, for instance by spraying the sawdust with rain water or by the use of a softening agent of similar type as is used at the washing of textiles. In this way treated sawdust can quickly and efficiently absorb floating pollutions where water is an essential component. Also oil and petrol can be absorbed. The absorbing capacity is sufficient to almost completely dry out an underlayer. One could say that the absoφtion means has a stronger suction effect on water than underlayers as concrete, asphalt, stone etc that therefor by means of the absoφtion means in accordance with he invention can be relieved of this. Alternatively to the treatment with a softening agent the teφene lacking sawdust may be treated with a teflon wax so that the dust particles get a coating of this. The sawdust treated in this way gets the property that it is hydrophobic and consequently different from the above described absoφtion means does not absorb water, at the same time the ability to absorb oil seems to be considerably improved. This absoφtion means is therefor very suited for use at oil discharges. The oil is not repelled by the teflon and this can pass into the respective sawdust particle and is there sucked into the spaces that originally were filled with teφenes. Since the absoφtion means is selective it can be used precisely for the control of oil petrol and the like without absorbing surrounding water, that but for this may be entirely clean. Since no water is bonded to the sawdust this will also after the absorbing of the oil float on water. In this way the absoφtion means after executed absorbing is easy to collect in comparison with many of the absoφtion means that exist on the market, which sink to the bottom and instead pollute this, which however is not visible but rather is more difficult to cure than the pollution on the surface.

The starting material used in accordance with the invention may be treated in different ways in order to become free from teφenes, as naturally essentially free from water. Sawdust may be composted or simply put in large heaps or piles that may decompose or "burn" so that the teφene content is reduced. When this has taken place, which take comparatively long time, the sawdust can be dried, then to be used as starting material at the fabrication of the absoφtion means according to the invention. The material made in this way will essentially be black.

Sawdust used in accordance with the invention may instead be dried forcefully and possibly quickly at a high temperature to drive out the teφenes from the dust. This may sound as a more expensive fabrication method but since the sawdust in any case must be dried and the burnt sawdust has turned out to be comparatively difficult to dry this is an economical alternative.

In a particular advantageous further development of the invention one instead of drying sawdust use fuel pellets or the waste resulting form the fabrication of fuel pellets from sawdust. The fuel pellets or waste material from its fabrication is then ground or disintegrated in some other mechanical way to the required fine grain.

Fuel pellets are made by heating that drives out the teφenes from the material and evaporate these as well as the water content, whereafter the material is pressed together to pellets. From pellets by following grinding etc in accordance with the invention made absoφtion means has turned out to be particularly efficient. An explanation of this might be that when the material freed from teφenes and water is compressed under high pressure practically all the separate cell structures collapse and the lignin in the still hot material then function as a glue holding the material together in the compressed form when the material is then allowed to cool off. When the material again is ground or worked in some other mechanical way the gluing is broken up and the cell structure can expand again. If the material also is subjected to a subsequent heating, as at the drying after adding of teflon the binding gluing ability of the lignin is reduced and the material can expand to an even more porous structure. A fact is that fuel pellets are so compressed that they do not float, why it already from this reason is not close at hand to use this as starting material for a material that is meant to float. After the grinding and in particular possible teflon treatment it however floats again.

Since the teflon is added before the final, by the heat achieved expansion of the particles the teflon will be situated on the tips of the particles, edges etc, that is the points that come in contact with for instance a water surface and secures hydrophobic properties. On the other hand no or only little teflon will end up centrally in the particles and the degree of use of the teflon is good and at the same time a minimum of teflon is used.

The absoφtion means according to the invention can be used in different ways and for instance may at a waste on a floor absoφtion means that has been treated with a softening agent be spread on so that water, petrol, oil etc is absorbed. The absoφtion means can then with absorbed liquids and in these possibly solved material in the normal case be destructed by being burned in a refuse incinerator together with ordinary garbage. The sawdust in itself is to be considered as fully environment friendly and in generals the liquids that have to be absorbed are entirely harmless if they are burnt. Most municipal incineration installations are also provided with equipment for cleaning of fumes, why it does not matter if a small amount of metals, for instance heavy metals should be in the oil that is absorbed. At discharge of petrol or oil on water, for instance in connection with the filling of boats the teflon wax coated variety of the absoφtion means in accordance with the invention may quickly be spread over the surface of the water then to be collected with a bag net after a while. Even here generally the oil or petrol that is spilled is in itself not dangerous for the environment provided that it is burnt and one can thus destruct the sawdust with accompanying oil by burning. At this of course the combustion heat in the sawdust as well as the oil or petrol is used.

As has been described above the absoφtion means according to the invention can be used in pulverized form and be scattered over the area that is to be treated. As a complement to this however the material may however be sewn into a suitable textile, for instance polypropylene fabric for the making of bars, sheeting, pads or hoses. In particular the hoses or bars can be joined together to connected barriers for the use on water, these barriers being filled the teflon coated variety of the invented means. The barriers are in their ends preferably provided with snap hooks that can hook into corresponding loops arranged on the sides of the barriers, this so that an overlap may be obtained for the separate barrier sections. Barriers made in this way can not only be used to confine an oil discharge as such but may also confine or hold this together when the oil has been absorbed by spread absoφtion means. By movement of the barriers the spread absoφtion means with absorbed pollution may be concentrated or moved in order to facilitate the collection and subsequent destruction. Since the absoφtion means floats of course also the barriers float.

The above suggested sheetings and pads respectively may for instance be used at damages and leakage on fuel or hydraulic system on working machines, tractors, lorries etc in a simple manner to take care of spilled oil. Since the means is enclosed it is easy to bring along. The sheetings may with advantage be constituted by two pieces of fabric of for instance polypropylene that have been sewn together so that longitudinal channels are achieved extending the entire length of the sheeting. In one end the channels may then be closable by means of sewn fast Velcro tapes. This makes filling and closing of the channels particularly simple. Furthermore the option to open a channel when needed to take out some absoφtion means is obtained, for instance if the ground on which the leakage has occurred is to uneven to allow absorbing directly with the sheeting as such.

Since the sawdust that constitutes the main constituent in the invention is free from teφenes it is also less volatile than dry sawdust otherwise is. The low ignition temperature for wood is namely ruled by the presence of the teφene. Without this the ignition temperature of the sawdust increase considerably and it need thus not be considered as inflammable. When the sawdust has been used and has absorbed oil or other combustible hydrocarbon the ignition temperature is ruled the ignition temperature of this and the absoφtion means is no longer difficult to ignite and burn. The variety of the absoφtion means according to the invention that includes teflon contains so small quantities of teflon that no risks exist and if, which is to be preferred, the absoφtion means and oil or some other pollution are burnt in a larger refuse incinerator installation the flue cleaning of this can handle the gas emitted by the teflon.

At previously known absoφtion means one has tried, or hoped to find means that are universally usable. The means according to the invention is not that universal and one has to choose if one or the other variety is to be used. In most cases it is however no problem to know in advance which type of absoφtion means that need to be at hand. Also one has generally when developing absoφtion means tried to find absoφtion means that can handle thick oil discharges. This is not the object of the invention even if it may function just as well for thick oil as many other means, at least to reduce the tackiness on the surface.

The invention is in its teflon coated variety in particular intended to be used at occasional alternatively regular small discharges of thinner oil as diesel oil, petrol etc.

Although it is desirable to be able to handle the catastrophes that thick oil discharges in the see constitutes, it is also important to control many small discharges in order to preserve the environment.

The fabrication of the means in accordance with the invention may in a simple manner be carried out in charges in a mixing drum, resembling those that are used for cement and concrete mixing, including internal vanes that are oblique so that rotation in one direction leads to discharging while rotation in the opposite direction means that the material is retained in the drum at the same time as mixing takes place. When the raw material for the invention, that is preferably atomized residues from the fabrication of fuel pellets have been filled in the drum this is rotated and the goods is tumbled in the drum. During this continuous tumbling of the material atomized jets or as a fog teflon that has been solved or emulgated in alcohol, for instance isopropanol, preferably the teflon wax may be "Hansa Prob 6804-S" distributed by Firma Cantarsia is sprayed into the drum.

An explanation of the exceptional suction ability and the absorbing capacity may be precisely the use of a wax as teflon wax that is difficult to solve, which for being solved require adding of for this intended tensides, that in a later phase when absorbing is to take place facilitates absorbing by reducing the surface tension for the oil that is to be sucked up. The tensides that thus are more or less a must for the use of a seemingly unsuitable hydrophobic agent are thus effective twice by means of teflon tensides. The solution is for instance prepared from 7 % teflon and the remaining part alcohol and this teflon solution is added in an amount corresponding to about 10% of the weight of the ready absoφtion means.

When the above given amount of teflon in solution has been added the drum will run yet a while for distribution over the surface of the chips so that the solvent of the teflon may evaporate during continued stirring and airing of the material. If desired this drying may of course be hastened by the adding of heat for instance in the shape of hot air or infra heat. When the alcohol has been dried away the rotational direction is changed and the oblique vanes of the drum feed out the ready absoφtion means, that by means of a band conveyor , screw conveyor or blowing can be transported to suitable filling stations for sacks, pads, barriers or bars.

The above fabrication method is of course also useful for the fabrication of the water absorbing absoφtion means variety. Here however the spraying of teflon solved in alcohol is exchanged for the injection of a suitable softening agent. With softening agent is here understood possible agents that reduce the degree of hydrophobic property that is obtained at the preceding hard drying of the starting material. At this variety it furthermore not necessary to dry the material after the mixing with the softening agent, since independent of if softening is done only with water or in the water solved softening agent, for instance "Pluronic (P6800)" from Basis Kemi AS so small amounts of water has to be added that the influence on the absorbing ability is unimportant.

In a yet more industrial scale the absoφtion means according to the invention may be made in an installation including a hopper for pellets, that in its lower end is provided with outlet feed mens, for instance feed screws, that transport the material to a hammer mill that breaks the pellets. The pellets are then transported further to a mixing chamber where teflon solved in water is added. The teflon wax is solved in the water in an amount corresponding to 5 to 10 in particular 7%. Furthermore pyro-acetic spirit (22%) is added in an amount corresponding to 2,5 - 5 % and in particular 3,5% of the volume of the solution, which has shown itself to improve the adherence and adhesion of the teflon on the wood material. The teflon wax solution is added in an amount corresponding to approximately 120 liters per m³ pellets.

The mixing chamber may for instance have the shape of a large diameter conveyor tube in which a feeding screw is arranged in the shape of a vane turned as a screw that is fastened to a central drive shaft by means of spokes that will expedite an efficient mixing at the same time as the material is slowly fed forwards by the vane that moves close inside of the inner wall of the chamber. In the wall of the mixing chamber, in particular on the upper side a number of inlet jets are arranged distributed over the length of the chamber for the adding of the teflon wax solution. From the mixing chamber the material is fed further on to a drying chamber with similar construction as the mixing chamber but with the difference that instead of jets an electric heating is arranged for the drying of the material, as well as an outlet for vaporized water. The drying temperature is preferably kept between 150 and 250 °C and can be controlled by the feeding speed or rather of the amount of water that one wishes to vaporize. The dried material is then by a screw transported further to a filling station.

If no hydrophobic agent is to be added the material in the mixing chamber may instead be admixed a softening agent, then to be fed directly to the packing station instead of being transported to the drying chamber.

The absoφtion means according to the invention may also be used as material in filters for the removal by filtering of oil and the like pollutions and at this the above mentioned sheetings may find use.

Claims

C L A I M S

1. Method for fabrication of absoφtion means from wood material in fine particles, for instance sawdust , characterized in that it in a first step is dried and in a second step is coated with teflon.

2. Method according to claim 1 , characterized in the teflon coating being achieved by the wood material in fine particles being sprayed and/or mixed with teflon solved or suspended in alcohol or water, and that when sufficient mixing has taken place the solvent (the water or the alcohol) is vaporized.

3. Method according to claim 2, characterized in that in the case of teflon dissolved in water acetic spirit is added to the solution before the mixing with the wood material.

4. Method according to any of the claims 1 - 3, characterized in that the wood material in fine particles has been made essentially or completely teφene free by heating.

5. Method according to claim 1 , characterized in the wood material being constituted of residue material from the fabrication of fuel pellets from sawdust alternatively of fuel pellets.

6. Method according to claim 1 , characterized in that the dissolving of the teflon in the alcohol or the water has been facilitated by tensides.

7. Method for fabrication of absoφtion means from wood material in fine particles, for instance sawdust , characterized in that it in a first step is dried and that it thereafter in a second step is softened by the adding of water or some other softening agent.

8. Method according to claim 7, characterized in that the wood material in fine particles has been made essentially or completely teφene free by heating.

9. Method according to claim 7, characterized in the wood material being constituted of residue material from the fabrication of fuel pellets from sawdust alternatively of fuel pellets.

10. Method according to claim 7, characterized in that the dissolving of the teflon in the alcohol or the water has been facilitated by tensides.

11. Method for the fabrication of absoφtion means of wood material in fine particles, for instance sawdust, characterized in that as starting material is used fuel pellets made of sawdust that are finely ground alternatively of residues from such fabrication.

12. Method according to claim 11 , characterized in the finely ground material being coated with teflon.

13. Method according to claim 12, characterized in the teflon coating being achieved by the finely ground wood material being sprayed and/or mixed with teflon dissolved or suspended in alcohol or water, and that when sufficient mixing has taken place the solvent (the water or the alcohol) is vaporized.

14. Method according to any of the claims 11, characterized in that in the case of teflon dissolved in water pyro-acetic spirit is added to the solution before the mixing with the wood material.

15. Method according to claim 11, characterized in that to the teflon has been added tensides.

16. Method according to claim 11, characterized in that the material is softened by the adding of water or some other softening agent.

17. Method for the fabrication of absoφtion means of wood material in fine particles, for instance sawdust, characterized in that in a first step it is dried to such an extent that existing teφenes have been vaporized.

18. Method according to claim 17, characterized in that the wood material in a second step is coated with teflon.

19. Method according to claim 17, characterized in the teflon coating being achieved by the wood material in fine particles being sprayed and/or mixed with teflon solved or suspended in alcohol or water, and that when sufficient mixing has taken place the solvent (the water or the alcohol) is vaporized.

20. Method according to claim 18, characterized in that in the case of teflon dissolved in water pyro-acetic spirit is added to the solution before the mixing with the wood material.

21. Method according to claim 17, characterized in the wood material being constituted of residue material from the fabrication of fuel pellets from sawdust alternatively of fuel pellets.

22. Method according to claim 18, characterized in that the dissolving of the teflon in the alcohol or the water has been facilitated by tensides.

23. Metiiod according to claim 17, characterized in that the material is softened by the adding of water or some other softening agent.

24. Absoφtion means of wood material in fine particles, for instance sawdust, characterized in that it is essentially teφene free after heating or some other treatment and that i also contains some water as softening agent.

25. Absoφtion means of wood material in fine particles, for instance sawdust, characterized in that it is essentially teφene free after heating or some other treatment and that i also contains teflon.

26. Absoφtion means according to claim 24 or 25 , characterized in that it further comprise tensides or softening agent.

27. Absoφtion means according to claim 24 or 25 , characterized in that it is enclosed in a pad (8), sheeting or bar of textile material, for instance polypropylene.

28. Absoφtion means according to any of the claims 24 27, characterized in that the pads, sheetings or barriers are provide with closable openings, for instance by means of

Velcro tape, partly for facilitating the filling partly for the use of the material in spread form.

29. Absoφtion means according to any of the claims 24 - 28, characterized in the wood material being constituted by coniferous wood or some other kind of wood with great initial content of terpene.